IgE detection to α/β/γ‐gliadin and its clinical relevance in wheat‐dependent exercise‐induced anaphylaxis

Wheat‐dependent exercise‐induced anaphylaxis (WDEIA) is characterized by anaphylactic reactions after wheat ingestion and physical exercise. IgE antibodies to recombinant ω₅‐gliadin are detectable in a majority of WDEIA patients, but other wheat allergens may also play a role in elicitation of WDEIA. Here, we performed a comprehensive analysis of IgE reactivity to different wheat proteins in 17 patients with confirmed WDEIA by ImmunoCAP research prototypes and a semi‐quantitative microarray immunoassay with α/β/γ‐gliadin, high‐molecular‐weight (HMW) glutenin, alpha‐amylase inhibitor (AAI) dimer, and wheat lipid transfer protein (LTP). By ImmunoCAP, IgE to recombinant ω₅‐gliadin was detectable in 14/17 patients (82%), to α/β/γ‐gliadin in 82% including the three patients lacking IgE to ω₅‐gliadin, and to HMW glutenin in 59%. The microarray revealed specifically γ‐gliadin as the second most important allergen. These results demonstrate the additional diagnostic value of α/β‐ and γ‐gliadin in particular in ω₅‐gliadin‐negative patients in the diagnosis of WDEIA.     

Pathophysiological mechanisms of exercise‐induced anaphylaxis: an EAACI position statement

This document is the result of a consensus on the mechanisms of exercise‐induced anaphylaxis (EIAn), an unpredictable and potentially fatal syndrome. A multidisciplinary panel of experts including exercise physiologists, allergists, lung physicians, paediatricians and a biostatistician reached the given consensus. Exercise‐induced anaphylaxis (EIAn) describes a rare and potentially fatal syndrome in which anaphylaxis occurs in conjunction with exercise. The pathophysiological mechanisms underlying EIAn have not yet been elucidated although a number of hypotheses have been proposed. This review evaluates the validity of each of the popular theories in relation to exercise physiology and immunology. On the basis of this evidence, it is concluded that proposed mechanisms lack validity, and it is recommended that a global research network is developed with a common approach to the diagnosis and treatment of EIAn in order to gain sufficient power for scientific evaluation.     

The utility of the ISAC allergen array in the investigation of idiopathic anaphylaxis

A diagnosis of idiopathic anaphylaxis following a detailed clinical assessment remains very challenging for patients and clinicians. Risk reduction strategies such as allergen avoidance are not possible. This study investigated whether the (ISAC) allergen array with 103 allergens would add diagnostic value in patients with idiopathic anaphylaxis. We extended the specific immunoglobulin (Ig)E testing in 110 patients with a diagnosis of idiopathic anaphylaxis from five UK specialist centres using ISAC arrays. These were divided into three groups: score I identified no new allergen sensitization beyond those known by previous assessment, score II identified new sensitizations which were not thought likely to explain the anaphylaxis and score III identified new sensitizations felt to have a high likelihood of being responsible for the anaphylaxis. A proportion (50%) of score III patients underwent clinical reassessment to substantiate the link to anaphylaxis in this group. The results show that 20% of the arrays were classified as score III with a high likelihood of identifying the cause of the anaphylaxis. A wide range of major allergens were identified, the most frequent being omega‐5‐gliadin and shrimp, together accounting for 45% of the previously unrecognized sensitizations. The ISAC array contributed to the diagnosis in 20% of patients with idiopathic anaphylaxis. It may offer additional information where a careful allergy history and follow‐on testing have not revealed the cause of the anaphylaxis.     

Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen

BACKGROUND: Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis. OBJECTIVE: We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP. METHODS: Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing. RESULTS: Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract. CONCLUSIONS: An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy.     

Food protein‐induced enterocolitis syndrome by fish: Not necessarily a restricted diet

Food protein‐induced enterocolitis syndrome (FPIES) is a non‐IgE‐mediated gastrointestinal food hypersensitivity usually due to cow′s milk or soy. Recent researches show that fish is 1 of the most important triggers of FPIES in the Mediterranean countries. Due to the risk of multiple‐food FPIES, avoiding foods in the same category or that often occur together may be reasonable. The aim of this study was to evaluate the evolution and follow‐up of FPIES related to fish over a period of 20 years. We describe the clinical features of our population, discuss different approaches to oral food challenges, and analyze the possibility of introducing the culprit fish or other nonrelated fish to avoid unnecessary restricted diets.